XYY Offender: A Modern Myth, The

Journal of Criminal Law and Criminology
Volume 62 | Issue 1
Article 4
1971
XYY Offender: A Modern Myth, The
Richard G. Fox
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Richard G. Fox, XYY Offender: A Modern Myth, The, 62 J. Crim. L. Criminology & Police Sci. 59 (1971)
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THE JoDRN.
oF CRIMINA
L&w, CRZIINOLOGY AND POLICE SCIEN CE
Copyright a 1971 by Northwestern Univerity School of Law
Vol. 62, No. 1
Printed in U.S.A.
CRIMINOLOGY
THE X
OFFENDER: A MODERN MYTH?
RICHARD G. FOX*
The issue of the English medical journal Lancet
published on August 26th, 1961, contained the first
report of an XYY human male.' The case was discovered in the United States in the course of an
investigation into the genetic background of this
particular man's two mongoloid daughters. This
first reported XYY male, was of average intelligence, physically unremarkable, and was not
drawn from a prison or mental hospital population.
Criminologists had no special reason to be interested in this new discovery.
Some two weeks before this report was published,
a 37 year old man by the name of Robert Peter
Tait broke into a house in a suburb of Melbourne,
Australia. While seeking money inside the house
Tait was disturbed by the occupant's 77 year old
mother. His response was to batter her to death.
Tait, who was on parole after serving almost two
years of a three year sentence for assaulting a 70
year old woman in 1959, and whose sexual satisfactions came from wearing or handling woman's
underclothes, from making compulsive sexual assaults on young women, and from inflicting pain
upon himself while masturbating, then removed his
latest victim's clothes, dressed himself in her undergarments, and subjected her body to certain bizarre sexual indignities.
At his trial for murder, his plea of insanity under
the McNaughten rules failed and he was sentenced
to death by hanging-a mandatory sentence for
those convicted of murder in the State of Victoria.
After the ordinary avenues of appeal had been exhausted, the government of the day announced
that it did not intend to commute the sentence of
death to one of life imprisonment although it had
invariably taken that step in relation to death
sentences over the previous ten years. This an* LL.M., Postgraduate Diploma in Criminology,
University of Melbourne; Associate Professor, Faculty
of Law and Senior Research Associate, Centre of Criminology, University of Toronto; Barrister and Solicitor
of the Supreme Court of Victoria, Australia.
I Sandberg, Koepf, Ishihara & Hauschka, An XYY
Human Male, 2 LANCET 488 (1961).
nouncement provoked the abolitionists into a
frenzy of legal and extra-legal steps to preserve
Tait's life. Apart from general arguments addressed
to the morality of the death penalty as a sanction,
the particular point was taken that Tait, though
not insane at the time of the offence or unfit to
stand trial, was nevertheless not liable to be executed because of insanity subsequent to trial. Reference was made to an old common law rule that a
person should not be hanged if he were found to be
insane in the period immediately preceding his
proposed execution. The only difficulty was that,
apart from the ordinary reactive depression and
anxiety state which reasonably accompanied the
prospect of his hanging, Tait exhibited no sign of
severe mental illness. The date of the hanging had
been set and revised on four occasions by the Cabinet before the High Court of Australia eventually
ordered an indefinite stay of execution pending a
further appeal. At that point the Cabinet's stubborn resistance crumbled and the sentence of death
was commuted. However, the Government insisted
to the very end that there was nothing in the circumstances surrounding the offence or in the acs
cused's mental state to warrant commutation.
Five years later, during a 1967 chromosome survey conducted at Pentridge Prisdn, Melbourne,
Tait was identified as a prisoner having an abnormal chromosome constitution, namely an XYY
chromosome complement.3 For reasons which will
2 The entire story is set out at length in 6 BURNs,
(1962). The appeals and other applications are variously reported in: R. v. Tait 119631 V. R.
520; Re Tait [1963] V.R. 532; Tait v. R. [19631 V.R.
547 and Tait v. R. 108 C.L.R. 620 (1963). See also
Feltham, The Common Law and the Execution of Insane
Criminals, 4 MELB.U.L.R. 434 (1963) and Howard,
Time and the JudicialProcess, 37 AusT.L.J. 39 (1963).
3 The anomaly was first reported as an XYY/XYYY
mosaic: Wiener, Sutherland, Bartholomew & Hudson,
XYY Males in a Melbourne Prison, 1 LA C'ET 150
(1968). Further study, however, revealed that his
karyotype was 47,XYY with a further genetic defect:
Wiener, Sutherland & Bartholomew, A Murderer with
47 XYY and an Additional Avlosomal Abnormality,
2 AuST. & N. Z. J. Cans. 20 (1969).
TaE TAIT CASE
RICHARD G. FOX
be considered later, it is doubtful whether recognition of this abnormality would have aided his plea
of insanity under the McNaughten rules. However,
in the view of the psychiatrist who attended Tait
in prison during the legal struggle for his life and
who advised the Government as to his mental
state, if Tait's chromosomal abnormality had previously been known, he would most probably have
had his death sentence quickly commuted on the
ground that the abnormality constituted sufficient
4
justification for the exercise of executive clemency.
The X-YY abnormality was first proffered as the
basis of a defense in 1968, at the Paris trial of
Daniel Hugon 5 Hugon was charged with murder
after strangling an elderly prostitute. His lawyers
initially raised the issue of XYY chromosome abnormality in relation to his fitness to stand trial.
The court appointed a panel of experts to determine
his competency and, when it was found that Hugon
was fit to stand trial, his lawyers took the position
that this genetic anomaly was the cause of his
violent behaviour. Hugon was convicted of murder,
but sentenced to only seven years imprisonment
because of extenuating circumstances. 6 Whether
these related to the circumstances of the offense itself, or the presence of the additional Y chromosome in Hugon, is not clear. The experts appointed
by the court denied that the extra Y chromosome
made men "born killers" but considered that it
brought on "troubles of comportment and hu7
mour".
Two years earlier in Chicago, Richard Franklin
Speck killed eight nurses in a rampage of rape, stabbing and strangulation. The fact that Speck was
over six feet tall, semi-literate (with an IQ of about
85), deeply pitted with acne, and had a history of
violent acts against women attracted the attention
of a number of geneticists who, in 1967 (after his
trial and conviction), conducted a chromosome
analysis on a sample of his blood. They reported
that he had an XYY chromosome complement.'
but the fact of this chromosome abnormality had
not formed part of the defense at the trial, nor was
4
Id. at 27.
1New York Times, April 21, 1968 at 1, col. 3; Trsm,
May 3, 1968 at 41.
6New York Times, Oct. 15, 1968 at 5, col. 2; T=u,
Oct. 25, 1968 at 75; Graven, Existe-t-il un "Chromosome du Crime?" 22 REv. INT. CRIU. & POL. TEcH-
NIQou 277, 277-78 (1968).
Toronto Globe and Mail, Oct. 15, 1968.
8 New York Times, April 22, 1968 at 43, col. 2; Teller,
Are Some Criminals Born That Way? 34 T iNK 24,
26 (1968); New York Times, May 6, 1969 at 93, col. 5.
[Vol. 62
it raised at subsequent appeals. In November 1968,
the Illinois Supreme Court upheld Speck's conviction for murder as well as the sentence of death. 9
The dosing months of 1968 saw further newspaper attention devoted to the XYY defect in the
reports of the trials of Lawrence Edward Hannell
in Melbourne, Australia and Ernst Dieter Beck in
Bielefeld, West Germany. Twenty-one year old
Hannell was tried for the apparently motiveless
murder by stabbing of his elderly landlady. Although evidence was adduced by the same psychiatrist who attended Tait to prove the existence of
an XYY chromosome defect in Hannell's body
cells, this fact did not significantly affect the jury's
determination that he was not guilty on the ground
of insanity since, on any interpretation of his conduct, Hannell was clearly legally insane within the
McNaughten rules.10 Beck, a 20 year old farm
worker, was sentenced to life imprisonment for the
murder of three women." Scientists informed the
court that Beck had an extra Y chromosome and
that this made him unable to control his impulses
to commit crimes ranging from house-breaking to
murder. The court, nevertheless, accepted the prosecution's argument that Beck was fully aware that
he was committing the murders even though he
might not have been able to control his impulse to
kill. There is no capital punishment in West Germany and Beck was sentenced to life imprisonment.
The fact that this was the maximum sentence possible casts doubt upon the view that the court was
favourably impressed by the XYY defense.
In April, 1969, in New York, Sean Farley a 6 ft.
8 in., 26 year old man pleaded not guilty on the
ground of insanity to a charge of raping and murdering a woman in an alley near her home. Farley
also exhibited the XYY chromosome abnormality
in his body cells but the jury rejected his defense of
9 However, after the State Supreme Court rejected
Speck's appeal, Associated Press reported his attorney
as announcing that Speck's chromosome structure
was normal. Speck's execution has been stayed pending
an 10appeal to the U.S. Supreme Court.
Bartholomew & Sutherland, A Defence of Insanily
and the Extra Y Chromosome: R. v. Hanndl, 2 AusT. &
N.Z. J. Cain. 29 (1968).
12Melbourne Herald, Nov. 12, 1968 at 3, col.-. The
first British murder trial of a known XYY male took
place at Lewes Assizes on 20 December 1968. The accused eventually was convicted of manslaughter. His
plea of diminished responsibility by reason of mental
abnormality was supported by medical reports without
the necessity of raising his genetic abnormality which,
as a consequence, was not specifically mentioned in
the court proceedings. See 1 BaiT. MED. J. 201 (1969).
19711
THE XYY OFFENDER
insanity and found him guilty of first degree mur- process fails to operate effectively individuals may
der.n
be born with either too few or too many chromoThe extensive publicity that has attended the somes. Numerous chromosomal abnormalities are
finding of genetic anomalies in the body cells of recognized. The XXY or Klinefelter Syndrome is
certain offenders has generated a great deal of pre- one in which the person is usually found to be outmature speculation and, consequently, much con- wardly male but sterile, somewhat mentally refusion. Before considering the present state of tarded and suffering from some breast enlargement.
knowledge, there are one or two definitional points This anomaly (which occurs in approximately one
to be cleared up. In general terms, chromosomes are out of every 400-500 male births) has been linked
threads of complex molecules (DNA) containing with anti-social behaviour, especially alcoholism
the genetic material which transmits hereditary and homosexuality, but as yet few findings of immessages from generation to generation of both portance have been published." XX Y males have
plant and animal life. These messages direct the de- also been discovered. These persons generally exvelopment of the offspring after fertilisation. The hibit the same physical features as XXY males but
number of chromosomes to be found in each plant the view has been expressed that the additional Y
or animal cell varies according to species. There are, chromosome may have a deleterious effect on the
for instance, two chromosomes in each cell of a development of their personality and, as a consesimple worm, fourteen in the garden pea, and quence, on their behavior. 4
forty-six in man. There is an exception to the genIt is, however, the XYY male who presently is
eral rule that each normal human cell has 46 of special interest to criminologists. 5 Although it
chromosomes. The female ovum and male sperm
1Mosier, Scott & Dingham, Sexually Deviant Becells respectively contain only 23 chromosomes but, havior
in Klinefelter's Syndrome, 57 J. PEDrATUcs 479
on uniting at conception, they pool their chromo- (1960); Court Brown, Sex Chromosomes and the Law,
somes so that the fertilized ovum contains 46 chro- 2 LANCET 508 (1962); Forssman & Hambert, Incidence
of Klinefelter's Syndrome Among Mental Patients, 1
mosomes. These are arranged in 23 pairs. As the LANCET
1327 (1963); Wigmanr & Smith, Incidence
fertilized ovum grows by division into a new in- of -linefelter's Syndrome Among Juvenile Delinquents
dividual, each of the 46 chromosomes also divides and Felons, 1 LANCET 274 (1963); Nielson, Klinefelter's Syndrome and Behaviour, 2 LANCET 587 (1964);
so that eventually each normal cell (other than Kvale & Fishman, The PsychologicalAspects of Klinesperm and ovum) contains the same number of felter's Syndrome, 193 J.A.M.A. 567 (1965); Casey,
Segal, Street & Blank, Sex Chromosome Abnormalities
chromosomes. Of the 23 pairs of chromosomes in in
Two State Hospitals for Patients Requiring Special
each cell one pair contain genes which determine, Security, 209 NATRE 641 (1966); Telfer, Clark, Baker,
among other features, the primary sexual charac- Richardson & Schmauder, Diagnosis of Gross ChromoErrors in Institutional Populations, 7 PENN.
teristics of the individual. In women this single pair somal
PsYcHIAT. Q. 3 (1968); Swanson & Stipes, Psychiatric
of chromosomes are of similar size and are called X Aspects of Klinefelter's Syndrome, 126 Am. J. PsYCAT.
chromosomes or, in the biologists' shorthand, XX. 814 (1969); Clark, Teller, Baker & Rosen, Sex Chromosomes, Crime and Psychosis, 126 Ams. J. PsYcHIAT. 1659
In the male this pair of chromosomes are unequal
(1970).
14 Court Brown, Sex Chromosome Aneuploidy in
in size; one of the pair is an X chromosome and is
and its Frequency, with Special Reference to Mental
larger than the other which is called the Y chromo- Man
Subnormality and Criminal Behaviour, 7 INT. REv.
some. In the biologists' shorthand, the male's sex Exp. PATH. 31 (1969).
"6The literature on XYY males is considerable,
chromosomes are described as XY. The primary
exceeding 200 articles in a wide range of professional
biological characteristics of masculinity are deter- journals, but mainly in the sphere of medical science.
mined by the Y chromosome. From this it becomes The leading articles in journals of a specifically criminoobvious that the sperm of the father, not the ovum logical or legal nature are: Mergen, Der Geborene
Verbrecher (Ein Bericht iiber Chromosomenforchung und
of the mother, determines the sex of the new in- Kriminologi),Kanm~axnAs
VEXAG (1968); Nielsen,
The XYY Syndrome in a Mental Hospital, 8 BaRr.
dividual. The character of the male sperm cell, X
J. Crs. 186 (1968); Bartholomew & Sutherland,
or Y, that fertilizes the ovum determines the sex of supra note 10; Wiener, Sutherland & Bartholomew,
the child. If the sperm contains a Y chromosome supra note 3; Fox, XYY Chromosomes and Crime, 2
& N.Z. J. Cam. 5 (1969); Graven, Le Problim
the child will be male; if the sperm contains an X AusT.
de I' "Anomalie Chromosomique XYY" en Criminologie,
chromosome the child is normally female. If this 23 REv. INT. C]MX. ET POL. TECONQuE 21 (1969);
Note, The XYY Chromosome Defense, 57 GEo. L. J.
New York Times, April 16, 1969 at 54, col. 6; April 892 (1969); Sergovich, Chromosome Aberrations and
24, 1969 at 53, col. 1; April 30, 1969 at 93, col. 4.
Criminal Behaviour, 11 Cam. L. Q. 303 (1969). Amir
RICHARD G. FOX
will be shown that the research findings are less significant than first reports suggested and that there
are strong psychological reasons for interest in the
topic, the flurry of recent attention has at least
provoked criminologists into re-examining the hith-
erto largely neglected field of criminal biology. The
new biological research is not simply a revamping of
Lombroso or Hooton, but is rather a continuation
and extension of the work of Kretschmer, Sheldon
and the Gluecks on the relationships between body
type, temperament and criminality. And, in the
final analysis, its importance lies less in the weight
of current findings than in the fact that the attempt
to identify the behavioral correlates of particular
genetic defects represents one of the important first
steps towards the ultimate elimination of undersirable traits in human beings by genetic manipulation. The attainment of this goal, however frightenening it may appear to be, is no fanciful dream; its
realization has been seriously predicted for the first
decade of the new century" and, with the recently
reported isolation of a single gene by Harvard scientists, this prediction may already require updating.
17
Dr. Mary Telfer of the Elwyn Institute of Pennsylvania has described the characteristics of a
person possessing an extra Y chromosome as "extremely tall stature, long limbs with strikingly long
arm span, facial acne, mild mental retardation,
severe mental illness (including psychosis) and
aggressive, anti-social behaviour involving a long
history of arrests, frequently beginning at an early
age". 18 Other writers have, however, warned that
& Berman, Chromosomal Deviation and Crime, 34 F.
PROn. 55 (1970); Baker, XYY Chromosome Syndrome
and the Law, 7 CRTvINOLOGICA 2 (1970); Russell &
Bender, Legal Implications of the XYY Syndrome, 2
S
S _ 'IN
PSYcHIATRY 40 (1970). Some extraordin-
[Vol. 62
there may be up to four distinct clinical manifestations of this syndrome only one of which includes
overgrowth, mental deficiency and criminal history. 9 Despite this warning, both popular and
professional writings on this subject have presented
their hypotheses in terms of XYY being linked
with tall, aggressive, anti-social individuals who
are found in unusual numbers in prisons and security mental hospitals.
Between the first report of an adult XYY male
in 1961, and the end of 1965, some 12 examples of
XYY males had been described as such in the
literature. They did not come from any particular
institutional or other setting, but were apparently
found fortuitously during the examination of males
suffering from some physical abnormality, often in
conjunction with a degree of mental retardation."0
The questions which are now being raised in relation to XYY abnormality and crime found first
expression in 1962 in a perceptive and prescient
letter written by the late Dr. William Court Brown
of Edinburgh to the journal Lancet. Dr. Court
Brown, noting a predisposition in chromosomally
abnormal males to "larceny, fire-raising, and indecent exposure" asked "whether such individuals
could be held in law to suffer from a diminished responsibility by virtue of their abnormal constitution?" 21 Court Brown's colleague, Dr. Patricia
Jacobs, pursued the matter further and initiated a
new phase of research with her publication of preliminary findings from a chromosome survey of
male patients in the maximum security State Hospital at Carstairs in Lanarkshire, Scotland.
The hospital, which is not a part of the prison
service, provides care for persons detained under
the Scottish Mental Health Act 1960 and who re-
quire treatment in conditions of special security on
ary research is being undertaken at the State University
of New York in breeding fish with an extra Y chromosome and comparing their behaviour with normal XY
male fish, see, Hamilton, Walter, Daniel & Mesler,
Competitionfor Mating Between Ordinaryand Supermale
Japanese Medaka Fish, 17 ANIMAL BEHA IOUR 168
(1969); Walter & Hamilton, "Supermales" (YY Sex
Chromosomes) and Androgen-Treated XY Males: Conpetitionfor Mating with Female Killifish, 18 ANIMAL BxHAvIOUR 128 (1970).
"KAHN
&
WEIxER, THE
YEAR
2000, 108-113
(1967); Fleming, On Living in a Biological Revolution,
ATLANTIC MoNThLY, March 1969; Further Thoughts
on the Biological Revolution, ATLANTIc MONTHLY April,
1969; Bender, Strack, Ebright & Haunalter, Delphic
Study Examines Developments in Medicine, 1 FuzuRxs
289 (1969).
"1New York Times, Nov. 23, 1969 at 1, col. 2.
18Telfer, Are Some Criminals Born That Way? 34
THINK 24 (1968). Similarly, Dr. John Money of Johns
Hopkins University has set out a composite image of
the XYY prisoner based on at least eleven variables
viz.: "broken family; difficult child; school history of
behaviour problems and under achievement; I.Q. av-
erage; E.E.G. probably abnormal; excessive daydream-
ing; socially alone; occupationally a drifter; unrealistic
future expectations; impulsive aggression and/or violence, but not an aggressive personality; bisexual or
homosexual and impulsive in sexual expression, with
no depth or continuance of affection". See Money,
Gaskin & Hull, Impulse, Aggression and Sexuality in
the XYY Syndrome, 44 ST. JoHN's L. R. 220,231 (1969).
19Carakushansky, Neu & Gardner, XYY
with
Abnormal Genitalia,2 LANcET 1144 (1968); Heinz, YY
Syndrome Forms, 1 LANCET 155 (1969).
20 Court Brown, Males With an XYY Sex Chromosome Complement, 5 J. MED. GENET. 341 (1968).
2 Sex Chromosomes and the Law, 2 LANCET 508 (1962).
12
Jacobs, Brunton, Melville, Brittain & McClemont,
Aggressive Behaviour, Mental Subnormality and the
XYY Male, 208 NATuRE 1351 (1965).
19711
THE XYY OFFENDER
account of their dangerous, violent or criminal
propensities. It was divided into one wing for those
classified as mentally subnormal and another for
those suffering from mental illness. At the time of
Jacob's survey, there were 342 male patients in the
hospital; 203 in the subnormal's wing and 139 in
the wing for the mentally ill. Patients were admitted in one or other of the following ways: (a) on
committal by the courts, (b) from penal institutions
where mental illness or mental subnormality was
diagnosed during the course of a prison sentence,
and (c) from other mental hospitals and hospitals
for the mentally subnormal whether or not they
had been admitted there on a court order.
Although it was possible that patients who had
not been convicted of criminal offenses could be
sent to this hospital, at the time of the chromosome
survey 249 of the 342 patients were admitted from
the courts. All but ten of the total number of patients had criminal records. By ascertaining
whether or not there was an increased frequency of
XYY males among mentally abnormal persons who
were detained because of their dangerous, violent
or criminal propensities, the research workers
hoped to test their hypothesis that an extra Y
chromosome predisposed its carrier to unusually
aggressive behavior. Jacobs and her colleagues were
only able to examine 315 of the 342 men and, of
these, 196 came from the subnormal's wing. The
preliminary report showed that twelve of the 196
men had an abnormal chromosome complement
(6.1%) and that this included 7 men with an XYY
sex chromosome constitution (3.6%). When the
survey was completed,2 another two XYY males
had been found in 119 men from the wing for the
mentally ill (1.7%). Altogether nine XYY males
were discovered in this initial survey of an institutional population-a frequency of almost 3%.
This figure alone has no significance until compared with figures on the frequency of the same abnormality in the general community. At the time
of the Carstairs hospital study this figure was not
known, though on theoretical grounds it had been
estimated to be in the vicinity of 1.3 per 1,000 live
births (0.1 3 %).u Actual chromosome counts of almost 10,000 new-born male infants in Scotland,
Canada and the U.S.A. have since indicated an
overall figure in the vicinity of 1.5 per 1,000
2
'Jacobs, Price, Court Brown, Brittain & Whatmore,
Chromosome Studies on Man in a Maximum Security
Hospital, 31 ANi. Hum. GENET. 339 (1968).
24 Court Brown, supra note 14 at 86.
(0.15 %). 2 The Carstairs findings therefore represented a twentyfold increase over the newborn incidence. However, the study was not able to reveal
whether the increased frequency of XYY males
found in the State hospital was related to their aggressive behaviour, their mental retardation or to a
combination of both these factors.
A particular point of interest was that the males
with XYY chromosomes were significantly taller
than the XY males in the institution and that, in
the group studied, a man 6 ft. or more in height had
approximately a 50% chance of having an XYY
constitution. The mean height of the men with a
single Y chromosome was 5 ft. 7 in., while the mean
height of the males with an extra Y chromosome
was 6 ft. 1 in.
In the following year another team of researchers
examined the tall men (6 ft. or over) at the English
maximum security hospitals at Rampton, Moss
Side, and Broadmoor and confirmed the findings of
Jacobs that stature was a useful marker for the
identification of the XYY male.2 6 Of the 50 males
found to be 6 ft. or more in height at the special
hospitals at Moss Side and Rampton, 12 had an
XYY complement and 4 of 50 from Broadmoor had
the same chromosome defect. Though the survey
findings from Moss Side and Rampton, in which
there was no screening on the basis of height, have
yet to be reported, the indications are that the
overall frequency of XYY males will be comparable
with the Carstairs hospital study with approximately 3% of the institution's population having
an extra Y chromosome.2?
Apart from their unusual height, the XYY males
21Sergovich, Valentine, Chen, Kinch & Smout,
Chromosome Aberrations in 2159 New-Born Babies, 280
NEw. ENo. J. Mxu. 851 (1969); Ratcliffe, Stewart,
Melville, Jacobs & Keay, Chromosome Studies on 3500
New-Born Male Infants, 1 LANCET 121 (1970); Lubs &
Ruddle, personal communication 1969, cited in Ratcliffe et al. ibid. p. 122; 'Walzer, Breau & Gerald, A
Chromosome Sitrey of 2,400 Normal Newborn Infants,
74 J. PEDIAmcS 438 (1969); Turner & Wald, Chromosome Patterns in a General Neonatal Population, Proceedings of the Pfizer International Symposium, Edin-
burgh, Scotland, 14-16 May 1969 (in press) cited in
Roebuck & Atlas, Chromosomes and the Criminal 15
CORRECTVE PSYCMHAT. 103 (1969). Each of the above
studies surveyed consecutive liveborn male infants.
Walzer however specifically excluded from his study
physically abnormal or unhealthy infants. If his study
is omitted from calculation, the incidence of XYY abnormality in newborn male infants will be shown as 19.
per 1000.
26 Casey, Blank, Street, Segall, McDougall, McGrath & Skinner, YY Chromosomes and Antisocial Behavior, 2 LAIcET 859 (1966).
' T Court Brown, suPra note 20 at 349.
RICHARD G. FOX
TABLE 1
FAmMLy HISTORY OF CRIMINAL CONVICTIONS
9 XYY
No. of parents convicted of crime.
No. of convictions ..............
18 Controls
0
0
1
1
31
1
63
No. of convictions ..............
1
139
No. of families with criminal
records* ....................
1
7
No. of siblings .................
No. of siblings convicted ........
12
* Excluding the records of the 27 patients.
in the Carstair's study have been shown to be
physically unremarkable and not different in any
significant bodily respect from a group of other patients in the hospital when matched for age, intelligence and stature.28 All appeared to be normally sexually developed. Similarly, in terms of
psychological test results, no significant differences
between the chromosomally abnormal group and
matched controls have been detected. 9 The behavioral characteristics of the nine XYY males at
Carstairs were subject to a detailed assessment and
were compared with a control group of eighteen
XY males randomly selected from the hospital
population. 0 All nine XYY male patients suffered
from a mental disorder which was classified as
"severe personality disorder of undetermined
cause" which, in most instances, was associated
with intellectual impairment. In this respect the
control group was almost identical to the XYY's.
There were, however, four ways in which the
XYY male differed importantly from the controls.
First, even though the patients in the two groups
had criminal records of comparable length, the
XYY patients displayed, in their criminal behaviour, less violence against persons than did
control patients. Thus, of the 210 occasions on
which the eighteen control males had been convicted, forty-six of these (21.9%) had been for
crimes against the person while 132 (62.9%) had
28Price, Strong, Whatmore & McClemont, Criminal
Patients with XYY Sex Chromosome Complement, 1
LANCET
565 (1966).
2
9 Hope, Philip & Loughran, Psychological Characteristics Associated with XYY Sex Chromosome Complement in a State Mental Hospital, 113 BIr. J. PsY-
carAT. 495 (1967).
'0
Price & Whatmore, Criminal Behaviour and the
XYY Male, 213 NATuRE -815 (1967); Price & What-
more, Behaviour Disorders and Pattern of Crime Among
XYY Males Identified at a Maximum Security Hos-
pital, 1 BRIT. MEn. J. 533 (1967).
[Vol. 62
been for crimes against property. On the other
hand, the nine XYY males had been convicted on a
total of ninety-two occasions, but only eight
(8.7%) of these convictions had been for crimes
against the person whereas eighty-one (88%) had
been for crimes against property. Only four of
the nine XYY males had been convicted of offenses
against the person compared with seventeen out
of the eighteen controls. This finding substantially demolished Jacob's original hypothesis
that an extra Y chromosome predisposed its
carrier to unusually aggressive behaviour and, to
this extent, the title of Dr. Jacobs 1965 preliminary report on XYY males now appears somewhat
inappropriate.
The second main finding in relation to the
Carstairs group of XYY patients was that, although their records included considerably fewer
crimes of violence against persons, they began
their criminal activities at a very young age (on an
average, five years earlier than the control patients). Three of the nine XYY males had been
convicted before the age of 10 years and the mean
age at first conviction for all was 13:1 years. None
of the eighteen controls had been convicted before
reaching 10 years of age and the mean age at first
conviction was, in this group, 18 years. Moreover, there was evidence in the case of more than
half the XYY males that they had been in trouble
with school authorities and police on account of
minor offences even before their first convictions.
Third, the research indicated that, among the XYY
patients, there was no significant family history
of crime or mental illness (see table 1).
The final observation made suggested that the
XYY patients were more resistant than others to
conventional corrective training and treatment.
From these studies by Jacobs, Casey, Price,
Court Brown and their various research teams, the
picture emerged of psychopathic individuals, often
standing out as the black sheep in otherwise reasonably well adjusted families. Aggression against
persons was not, however, an important feature
of these men, although later reports of individual
XYY cases have shown that XYY males can be
extremely aggressive." Even though some "nor3"See, e.g., Teller et al., supra note 13 at 7; Wiener,
et al., supra note 3; Persson, An XYY Man and His
Relatives, 11 J.MIENT. DExic. Rxs. 239 (1967); Matthews & Brooks, Aggression and the YY Syndrome, 2
LANCET 355 (1968); Cowie & Kahn, XYY Constitution in PrepubertalChild, 1 BRIT. VIED. J.748 (1968).
Reference must also be made to the cases of Tait,
Hugon, Speck, Beck, Hannell and Farley referred to
earlier.
1971]
THE XYY OFFENDER
mal" XYY individuals have been reported, it is
upon the Scottish findings of an increased incidence
in institutional populations, and upon their
description of the behavioral characteristics of
XYY men, that most later research has been
based. The Carstairs study is not presented as a
model piece of scientific investigation. The samples
are too small to exclude the risk of gross statistical
error; and the bulk of information on the criminality of XYY males is based on information
derived from surveying groups of men, the majority
of whom are known to have criminal records.
Nevertheless, Jacob's work remains important
as the bench-mark from which all subsequent
research has taken its direction.
The stage of research has now been reached in
which information is being gathered on the frequency and characteristics of extra Y men in
diverse samplings of male populations. The surveys
have included groups of men in prisons and mental
hospitals, juvenile delinquents, and samples of
non-institutionalized "normal" males. The classification, for comparative purposes, of available
surveys findings is an exercise of extremely doubtful validity and, therefore, care must be taken
not to over-interpret the few facts that are already
in hand. A number of important limiting factors
should be kept in mind. The tabulation of the
populations surveyed into Adult Prisoners, Criminally Insane Offenders, Mental Patients, Juvenile
Offenders and Non-Institutionalized Populations,
is, of necessity, somewhat arbitrary owing to the
brief fashion in which the institutions under study
are usually described in the presentations of
research findings. There has been negligible standardization of research in terms of the type, purpose
and location of the institution or agency whose
population is sampled, the general physical, mental
or social characteristics of the entire group from
which the research sample has been selected, the
period of time over which the survey has been
conducted, and even the particular laboratory
procedures used for the identification of chromosomal abnormalities. Similarily, the variations
32See Wiener & Sutherland, A Normal XYY Man,
2 LAwcE 1352 (1968); Stenchever & MacIntyre, A
Normal XYY Man, I LANCE 680 (1969). In 1968
Court Brown, Price & Jacobs published information
on a further 15 XYY males emphasising their apparently normal sexual development and the fact that they
were to be found in various sectors of the community
and not merely in prisons or maximum security hospitals. There was however considerable evidence of
behavioural disturbances in this group: Court Brown,
Price & Jacobs, Further Information on the Identity of
47 XYY Males. 2 BRT.Mic). T. 325 (1968).
in sample size are considerable. It will be seen
from table 2 that in chromosome surveys of
populations not defined by height, the sample
size has ranged from 50 to 607 persons. But, with
regard to the expected frequency in the normal
population of only I or 2 XYY cases per thousand,
the sample size is clearly inadequate."
A number of different screening devices have
been utilized by researchers in an attempt to
expedite the discovery of persons with an extra Y
chromosome complement. Height (6 ft. and
over) is the primary screening device used and,
as can be seen from table 3, it does increase the
probability of identifying XVY males. However,
it is important to note that the height limitation
set by different researchers varies from 5 ft. 9 in.
to 6 ft. 2 in. and that it is sometimes used in conjunction with further screening on the basis of low
intelligence and/or aggression. Moreover, it is
dear that not all of the screening criteria used by
the various researchers have been made explicit
in their published reports and there is reason to
believe that, on this ground, a number of the
findings should be viewed as unrepresentative."
Not only is comparison of results complicated
by the differing criteria used in the choice of research subjects, but also, in most cases, little
attention is given to the identification and analysis
of the particular selection factors and admission
criteria which determine the type of man found in
the institution. Because certain facilities bear
similar titles and appear to serve the same purposes, it does not necessarily follow that they
contain homogeneous populations. The existence
of different population profiles is a likely explanation of why outwardly comparable institutions
contain significantly different distributions of
XYY males.
Tables 2 and 3 reveal that, to date, surveys of
non-institutionalized adult populations (whether
height screened or not) have failed to find any
cases of XYY abnormality. Because of the heavy
weighting of married males provided by the
groups attending subfertility clinics and the fact
that over half of the 207 men in the Edinburgh
general practices sample were 65 years or older,
these findings cannot be taken to be representative
of the normal non-institutional population at
3The
Centre of Criminology, University of Toronto
in conjunction with the Department of Pathological
Chemistry and Banting Institute is planning an XYY
chromosome survey in different male populations using
1000 as the minimum sample size in each group. The
Johns Hopkins University in Maryland is planning a
project involving two samples of 7,500 each.
[Vol. 62
RICHARD G. FOX
TABLE 2
PREVALENCE OF XYY MALES IN POPULATIONS UNSCREENED ON BASIS OF HEIGHT*
Adult Prisoners
" . . . . . . . . . . . . . . . . .. . .. . .. . . . . . . . . . . .
Grendon Prison for recidivists, England .
Allocation centre, Saughton Prison, Edinburgh, Scotland (males sentenced to one
. . . . . . . . . . . .. . . . . .. . .. . .. . .. . .. .. . . . . . . . . . . . . . . . . . . . .
35
year or more) ....
Criminally Insane Offenders
3
Hospital for the Criminally Insane, Ontario, Canada
XYY
XYY
204
2
0.98
302
0
506
2
0.39
230
4t
1.73
607
57
1
1
0.16
1.75
664
2
0.30
315
605
9
0
2.85
-
920
9
0.97
207
135
50
143
0
0
0
0
-
535
0
-
72
1
1.38
2927
18
0.61
Examined
Population Surveyed
. . . . . . . . . . . . . . . . . . . . . . . . .
Juvenile Offenders
New entrants, Scottish Borstals for one year ................................
Detention home and court psychiatric referrals, New York State3 ...............
Mental Patients
Maximum Security Hospital, Carstairs, Scotland3 .............................
. . . . . . . . . . . . . . . . . . . . .
0
Mental Subnormality Hospital, England ..
. . . . . . . . . . . . .
Non-Institutionalized Population
41
Randomly selected adult males, Edinburgh (general medical practices) .........
2. . . . . . . . . . . . . . . . . . . . .
Males attending a subfertilty clinic, Uppsala, Sweden
43 . . . . . . . . . . . . . . . . . .
Males attending a subfertility clinic, Edinburgh, Scotland
44
Males attending a subfertility clinic, Edinburgh, Scotland .....................
Other
Epileptic Colony, Edinburgh" ..............................................
Totals .............................................................
. ..
. . .
-
* Newborn infant surveys have been excluded from this table-see supra, note 25 and accompanying text.
t Includes one XYYY.
34Bartlett, Hurley, Brand, & Poole, Chromosome of
Male Patients in a Security Prison, 219 NATURE 351
(1968).
35Unpublished Edinburgh data, see Court Brown,
supra note 20 at 354.
36 Sergovich, supra note 15 at 307.
3 Note 35 supra.
-1 Marinello, Berkson, Edwards & Bannerman, A
Study of lhe XYY Syndrome in Tall Men and Juvenile
Delinquents, 208 J.A.M.A. 321 (1969).
39Jacobs, et al., supra, notes 22 and 23.
40 Note 35 supra.
41Court Brown, Buckton, Jacobs, Tough, Kuenss-
berg & Knox, Chromosome Studies on Adults, 42 EuGENICS LABORATORY MONOGRAPH (1966).
42 Kiessler, Karyotype, Meiosis and Spermalogenesis
in a Sample of Men Attending an Infertility Clinic, 2
MoNoGAPHS
IN HuMAN GENETICS (1966).
43
McIlree, Price, Court Brown, Tullock, Newsamn &
Maclean, Chromosome Studies on Testicular Cells from
50 Subfertile Men, 2 LANcET 69 (1966).
44 Note 35 supra.
45Id.
4
6Especially Goodman et al., infra note 49 and
Wiener, et al., supra note 3. See the comments by Court
Brown, supranote 20 at 356.
19711
THE XYY OFFENDER
TABLE 3
PREVALENCE 0
XYY MALES IN POPULATIONS SCMNnn
Screening Criteria
Population Surveyed
Adult Prisoners
Nottingham Prison, England' 7
4s
Institution for defective offenders, Patuxent, Maryland
ON BASIS OF HEIGHT
NO.
Examined
%
XYY
No.
XYY
ht. >-6 ft.
ht. 6 ft.; W.A.I.S.
24
10
2
0
8.33
-
<75
ht. >_6 ft.; ag-
10
0
-
gressive
ht. >6 ft. 2 in.
State Penitentiary, Ohio'"
°
H. M. Prison, Wandsworth, London, England"
H. M. Prison, Pentridge, Melbourne, Australia"
Penal Institution for unselected delinquent adults, PennsylvaniaPenal institution for mentally defective adults, PennsylvaniaAll prisons, Scotland"
s
State Prison, Attica, New York State
6
Prison, New York State
Criminally Insane Offenders
Hospital for the criminally insane, Pennsylvania"
Institution for criminal psychopaths, Herstedvester, Denmark"
Criminal psychiatric patients, New York State"
Juvenile Offenders
6
Detention Centre for juvenile delinquents, Pennsylvania '
Delinquent boys (12-19 years) in approved schools, England'
Institution for young offenders, Scotland"
Detention Centre, Scotland"
Mental Patients
Maximum security hospital, Scotland 64
MaximumsecurityhospitalsEngland: 65mentallysubnormal
mentally ill
66
Institution for mentally ill, England
State hospital, Atascadero, California6
State mental hospital, Denmark"
Hospital for mentally subnormal and psychiatric cases
England 6 '
Mental hospitals, Sweden 7 '
n
State mental hospital, Arhus, Demnark
Mental subnormality hospitals, Scotand
r
Mental subnormality hospital, England
Mental disease hospitals, Scotland'
22
1
4.54
>-6 ft. 1 in.
>6 ft.
>-5 ft. 9 in.
>5 ft. 11 in.
100
34
34
35
2
2
4
2
2.00
5.88
11.76
5.71
ht. >5 ft. 11 in.
30
0
-
106
86
5
1
2
0
0.94
2.32
-
lit.
ht.
lit.
ht.
ht. >6 ft.
ht. >-6 ft.
lit. >6 ft.; aggressive
-
-
-
496
16
3.22
lit. >5 ft. 11 in.
lit. >5 ft. 11 in.
50
37
2
2
4.00
5.40
ht. >-6 ft.; aggressive
18
1
5.55
105
5
4.76
14
29
1
3
7.14
10.34
16
4
1
0
6.25
-
63
5
7.93
ht. >5 ft. 11 in.
ht. -90th percentile
for age
ht. >6 ft.
lit. >-6 ft.
ht.
lit.
ht.
ht.
ht.
lit.
ht.
>6 ft.
>-6 ft.
>-6 ft.
>6 ft.
>6 ft.
>S ft. 11 in.
>6 ft.
21
50
s0
30
120
23
19
5
12
4
0
4
3
2
23.80
24.00
8.00
ht.
ht.
ht.
ht.
ht.
>6 ft.
>5 ft. 11 in.
>6 ft.
>6 ft.
>-6 ft.
96
41
39
21
112
3
0
3
5
1
3.12
7.69
23.80
0.89
-
3.33
13.04
10.52
RICHARD G. POX
[VCol.62
TABLE 3-Continued
Population Surveyed
Mental Patients
Mental hospitals, Wisconsin7 5: maximum security
mentally retarded
State mental hospital, New York State7 6
Psychiatric patients (4 institutions), New York State77
Non-institutionalized Populations
"Normal" male population, England78
College basketball players, Ohio79
Industrial population, Scotland 8o
White "normal" male volunteers, New York State"'
Screening Criteria
No iN
o.
%Y
ht. >--6
ft.
ht. >6 ft.
ht. >6 ft.
ht. >6 ft.; aggressive
210
32
76
26
10
1
1
0
4.76
3.12
1.31
-
966
54
5.59
30
36
371
30
0
0
0
0
-
467
0
-
2097
80
ht. >6 ft.
ht. >5 ft. 11 in.
ht. >6 ft.
ht. >6 ft.
Totals
large. However, they do point to the existence of a
gap between the numbers found in prisons, hospitals for the criminally insane, mental hospitals
and centres for juvenile delinquents and those in
the wider community. Why tall juvenile offenders
and mental patients, as discrete groups, should
provide the highest percentages of XYY cases is
not clear. Since juvenile offenders and mental patients are ordinarily seen as needing treatment
rather than as deserving punishment they are,
paradoxically, likely to be confined in an institution
4 Casey et al., supra note 26.
4
8 Welch, Borgaonkar & Herr, Psychopathy, Mental
Deficiency, Aggressiveness and the XYY Syndrome, 214
NATURE 500 (1967).
49Goodman, Smith & Migeon, Sex Chromosome Abnormalities, 216 NATURE 942 (1967).
50Griffiths & Zaremba, Crime and Sex Chromosome
Anomalies, 4 BrT. MED. J. 622 (1967).
51Wiener, el al., supra note 3.
2Telfer, Baker, Clark & Richardson, Incidence of
Gross ChromosomalErrorsAmong Tall Criminal American Males, 159 SCiENCE 1249 (1968).
63Id.
54 Unpublished Edinburgh data, see Court Brown,
supra note 20 at 355.
5' Marinello, et al., supra note 38, p. 321.
56Abdullah,
Jarvik, Kato, Johnston & Lanzkron,
Extra Y Chromosome and its PsychiatricImplication, 21
ARcH.
57
GEN. PSYCHIAT.
Note 52 supra.
497 (1969).
0 Nielsen, Tsubol, Stump, & Romano, XYY Chro-
mosomal Constitution in Criminal Psychopaths, 2 LANcET 576 (1968).
59Note 56 supra.
60Note 52 supra.
61Hunter, Chromatin-positive and XYY Boys in Approved Schools, 1 LANCET 816 (1968).
62 Note 54 supra.
3.81
for a wider range of behavior than would normally
be seen as justifying strict imprisonment. It is
thus open to the speculation that, if in fact the
extra Y chromosome is linked with impulsive forms
of anti-social conduct, populations of institutionalized juvenile offenders and mental patients will
represent more variant forms of such behaviour
and, consequently, will disclose more XYY cases.
In addition to the 98 XYY cases discovered in
the above surveys, at least a further dozen have
been individually identified because of their severe
4
Note Id.
Jacobs, et al., supra, notes 22 and 23.
47 supra.
65Note
66Id.
67Thompson (1967), personal communication cited
in Court Brown, supra note 20 at 355.
rs Nielsen, The XYY Syndrome in a Mental Hos-
pital, 8 BRIT. J. CRas. 186 (1968).
89 Close, Goonetifleke, Jacobs & Price, The Incidence of Sex Chromosome Abnormalities in Mental Subnormal Males, 7 CYTOGENETics 277 (1968).
70 Akesson,
Forssman &Wallin, Chromosomes of Tall
Men
7 in Mental Hospitals,2 LANCET 1040 (1968).
1 Nielsen, Y Chromosomes in Male Psychiatric Patients above 180 cm. Tall, 114 BRIT. J. PsycinAT. 1589
(1968).
72
73 Note 54 supra.
74
Id.
1d.
75 Daly, Neurological Abnormalities in XYY
221 NATURE 472 (1969).
Males,
Note 55 supra.
56 supra.
78 Note 47 supra.
76
77Note
79Goodman, Miller & North, Chromosomes of Tall
Men, 1 LANCET 1318 (1968).
80Note 54 supra.
" Note 55 supa.
THE XYY OFFENDER
behavioral problems and unusual height. Thus, in
the five years following Jacobs' first report of
institutionalized XYY males, more than 100 cases
have been described in the literature. Since the
bulk of this subsequent research has involved
surveying populations of males held in institutions
for the psychiatric or behaviorally deviant, it is
hardly surprising to find that the majority of
extra Y males detected have had a history of antisocial behavior. Nevertheless, this has been widely
interpreted as indicating that XYY individuals are
predisposed to anti-social and criminal behavior
and has led to the hypothesis that XYY individuals
can be shown to differ significantly from chromosomally normal males with respect to behavioral
and other characteristics. It cannot be denied
that there is evidence that gross chromosomal
abnormalities are found in small but unexpected
numbers of males who become institutionalized for
criminal or abnormal psychiatric behavior; but
the stage at which it is meaningful to talk of an
XYY syndrome in Dr. Telfer's terms has certainly not been yet reached. The Scottish researchers have consistently been unwilling to
state any case stronger than, that by comparison
with an XY male, an XYY individual incurs some
increased risk of developing a psychopathic personality through the quantitative evaluation of
this enhanced risk is not yet possible. Certainly, in
their opinion, there is no evidence that an XYY
male is inexorably bound to develop anti-social or
criminal traits.P
Not only is additional systematic investigation
of the incidence of XYY abnormality in selected
populations required, but almost every aspect of
the morphology of the XYY male demands a great
deal of further study. For example, a comparison
of tables 2 and 3 indicates that when the population examined is defined according to height, the
probability of identifying XYY males is largely
increased. However, unless the study systematically samples the full range of height in the population surveyed, no comparison of height/XYY frequency correlates can be made between different
groups which may vary in height. Moreover, there
is evidence that significant numbers of XYY
individuals are not abnormally tall. When a listing
is made of the heights of all adult XYY males
identified in the literature in circumstances in
which height was neither a screening device nor a
factor influencing the undertaking of chromosome
8
Court Brown, Price & Jacobs, TIx XYY Male, 4
Afro. J. 513 (1968).
BRIT.
studies, it is found that the height range commences at 5 ft. 7 in. and extends to 6 ft. 5 in. with
a mean of 6 ft.P This data, when tabulated, suggests that approximately 50% of adult XYY's
will be under 6 ft. in height. This means that
chromosome surveys limited to men of this height
or greater, risk failing to detect 50% of the XYY
cases likely to be present. And, even if the height
limitation is set at 5 ft. 10 in., approximately 25%
may still be missed. The contention that overgrowth is the outstanding morphological characteristic of extra Y males may also be assailed on a
number of other grounds.
On the one hand there is the problem of taking
into account factors which exert a restraining
influence on bodily growth. For example, malnutrition in childhood, especially in those born
before the postwar improvements in nutritional
standards, and mental subnormality, commonly
reported in XYY men, is, itself, known to affect
stature. On the other hand, and probably of greater
importance, is the likelihood that some males with
an XYY constitution come from families with an
established tendency towards tallness. In several
cases it has been found that the chromosomally
normal siblings (both male and female) of a tall
institutionalized XYY male were of similar height
to their abnormal brother." In the family history
of the tallest XYY man so far reported, a Jamaican
measuring 7 ft. 534 in., it was stated that his father
was of similar height and that all his living siblings
were also tall Again, the first report of a Mexican
with an extra Y complement came about as the
result of an investigation into the genetic background of this man's two unusually tall
daughters3 6
If the extra Y chromosome is simply linked with
overgrowth it is plausible to argue that individuals
who are in fact taller and heavier in stature may
be particularly susceptible to the risk of imprisonment because their great build and height presents such a frightening picture that courts and
psychiatrists may be biased in directing them
towards mental hospitals or prisons for community
safety.P Such an hypothesis has the advantage of
83Court Brown, supranote 20 at 350.
"4Wiener et al. suPra, note 3; Jacobs, et al., supra
note 23.
8 Thorburn, Chutkan, Richards & Bell, XYY Chromosomes in a Jamaicanwith OrthopaedicAbnormalities,
5 J.6 KME.GENETics 215 (1969).
a Lisker, Zenzes & Fonesca, XYY Syndrome in a
Mexican, 2-LAcT 635 (1968).
7Hunter,
YY Chromosomes and Klinefdter's Syndrome, 1 LANCET 948 (1966).
RICHARD G. FOX
being more parsimonious than one which postulates
that the XYY genotype, in some hitherto unknown manner, finds phenotypic expression in
particular types of anti-social behavior.
A variety of other physical, neurological and
physiological abnormalities have been described
as being associated with the finding of an additional
Y chromosome. These include anomalies of the
genital tract, varicose ulceration of the legs, acne,
abnormal EEG and ECG findings, and elevated
levels of the hormone testosterone (largely responsible for the full development of male secondary
sex characteristics). These and other findings
have been critically reviewed at length elsewhere' s
and it is sufficient for present purposes to observe
that they are, to say the least, equivocal. Even the
widely affirmed connection between mental subnormality and XYY has been challenged with the
recent finding of males with normal and above
normal IQ.'s. 9
An editorial annotation in the Australian and
New Zealand Journal of Psychiatry has suggested
that XYY research "might well lead to the delineation of a clear cut constitutional psychopath from
the present amorphous mass of psychopathic
personalities",Y° This is an interesting speculation
since the English psychologist Hans Eysenck has,
for some time, been arguing controversially for
acceptance of a modern version of the Lombrosian
notion of the "bor criminal" on the basis of the
existence of "some kind of gene, chromosome, or
other structure which could be the physiological
or neurological basis for differences between the
criminal and non-criminal kind of person". Eysenck's theory is probably far too broad, but it
would be of considerable interest to ascertain
whether 'XYY psychopaths" bear any of the
modem Eysenckian "stigma of criminality"
-high scores on measures of extraversion and
low ones on measures of conditionability. 91
It might be thought premature to speculate on
the significance in the criminal law of such an ill
defined theory and one whose viability, in any
form, is so uncertain. Yet, as has already been
noted, reference to the accused's abnormal genetic
8 Kessler & Moos, The XYY Karyotype and Criminality: A Review, 7 J. PsYcusAT. REs. 153 (1970).
s In one case an XYY male with an I.Q. of 125 was
reported. See Borgaonkar, Murdock, McKusick, Borkowf, Money & Robinson, The YY Syndrome, 2 LAN-
CET 461 (1968).
90Bartholomew, The Extra Y Chromosome and
Criminal Behavior, 2 AusT. & N.Z. J. PSYcHiAT. 6
(1968).
91H. EYSENC K, CmIM AND PERSONALTY (1964).
[Vol. 62
make-up has been made in a number of criminal
trials-inevitably in support of a plea of insanity.
But in no case known to the writer has the presence
of an extra Y chromosome proved to be an adequate basis for a successful defense. The demonstration of this genetic defect in the body cells of a
defendant has not yet impressed the courts in
their consideration of his criminal responsibility,
nor is it likely to have any effect on them in the
immediate future. Until scientists are able to
enunciate, in fairly precise terms, the behavioural
impact on a person of this abnormality, the courts
are wise to retain their skepticism.
Whether the defense of insanity rests on the
view that insanity is a cognitive or behavioural
disorder, or a combination of both, the overriding
problem of establishing some causal connection
between the accused's chromosomal anomaly and
his mental functioning remains.9 2 Under formulations based on the McNaughten rules the onus
is upon the accused to prove that at the time of
the act he was incapable of either appreciating
the nature and quality of his conduct or knowing
that it was wrong. If one puts aside those XYY
individuals who are found to be also suffering
from severe mental illness or retardation which
is productive of cognitive incapacity, it would
appear, in the present state of knowledge, that
possession of the extra Y chromosome does not
itself affect a person's ability to appreciate either
the nature and quality of his aggressive or criminal acts or that they are wrong. Thus proof of this
particular chromosomal abnormality would not,
alone, sustain a plea of insanity under this test.
In those jurisdictions in which insanity is
recognized as a behavioural disorder, the defense
of insanity is founded on the incapacity of the
accused to control his actions. This often takes
the form of the defence of "irresistible (or uncontrollable) impulse" or the limited defense of
"diminished responsibility". However, until the
alleged nexus between the chromosomal abnormality pleaded by the accused and his poorly controlled aggression can be more clearly demonstrated, these defenses too are doomed to failure.
In any event, the result of a successful plea of
insanity usually is indeterminate detention in
91For an extended discussion of the relevance of the
XYY syndrome to the M'Naghten, IrresistibleImpulse,
Durham and Model Penal Code tests of insanity, see,
Note, The XYY Chromosome Defense, 57 GEo. L. J.
892 (1969). The Australian situation is described in
Fox, XYY Chromosomes and Crime, 2 AuST & N.Z.
J. Cams. 5 (1969).
THE XYY OFFENDER
1971]
either a prison or security hospital. The strategic
advantage of this defense is found in escape from
the death penalty or, in those jurisdictions in
which capital punishment has been abandoned,
in the hope that the period of indeterminate
detention will turn out to be shorter than the
sentence of life imprisonment or fixed sentence in
commutation of the death penalty. However, in the
latter case, since the implication is that the chromosomal defect relied upon in establishing the defense
of insanity is a chronic and unchangeable condition, the accused may find that his defense, in
terms of expediting release, is no defense at all.
It is interesting to consider why XYY chromosome abnormality so quickly caught both the
public and professional imagination. A search of
the literature discloses that there have been more
than 200 articles in professional journals in the
fields of medicine, science, psychology, law and
criminology since 1965.13 Buttressing this interest
has been considerable newspaper publicity. Part
of the attention is, undoubtedly, the result of the
murders which have been associated with a finding
in the defendant of an XYY constitution. Again,
some of the attention has derived from interest in
XYY abnormality as a possible defense to a criminal charge; but, since XYY has been notably
unsuccessful in this regard, it is hardly a case of
lawyers delighting in finding new grounds of
exculpation for their clients. The answer may lie
at a deeper level.
In the pre-Freudian era of simplistic explanations of human behaviour, the view was largely
held that behaviorally abnormal individuals,
whether psychologically or criminally deviant,
were qualitatively different from the wider normal
population. The bizarre conduct of the abnormal
person was due to possession by demons or, in
Lombrosian terms, an atavistic throwback to
earlier animal stages of existence, and bore no real
relationship to normal conduct. It was important,
therefore, that these people be isolated for they
appeared to be dangerously different not merely
in degree, but in terms of significant qualities.
13In June 1969 a conference on the XYY Syndrome
was held in the U.S. under the auspices of the N.I.M.H.
Centre for Studies in Crime and Delinquency and, in
December, a similar conference was held in England
under the sponsorship of the Institute of Criminology,
Cambridge, CRIM[NOLOGIcAL IMPLICATIONS OF CmEOmosomE ABNORMALITIES (West ed. 1969). See also PROCEE:DNGS O THE SyMposium ON CHRoMosoME ABNORMALITY
AND
CRIMINAL
REsPONsIBILITY,
HEBREW
UNIVERSITY OF JERUsALEm INSTiTuTE OF CRIMINOLOGy
(1969).
The behavioral scientists of the 20th century
have propagated a different message. Possibly
Freud's greatest contribution to the understanding
of human behavior was that mentally-iU persons
were not qualitatively different from the normal
population and that mental illness was only a
matter of degree. The garbled utterances of a
schizophrenic patient were not meaningless
sounds, but could be interpreted and, on interpretation, would realize meanings bearing remarkable resemblance to the thought processes of
normal persons. Criminals too were not qualitatively different from non-criminals. Members of
both groups had within themselves propensities
for murder, rape, incest, theft and criminality in
general. The differences between the groups lay
more in the internalized controls and external
constraints which modified the expression of their
criminal potential than in any inherent difference
between them. To be reminded of this essential
similarity is not comforting, especially for those
who believe themselves to fit clearly into the
non-offender classification. And yet, since the time
of Freud, social scientists in a variety of ways
have been emphasizing and re-emphasizing the
blurred distinction between, "normal" and "abnormal", criminal" and "non-criminal". Particularly in the last few years, this process has been
carried forward so as to challenge the very concepts of crime and mental disorder themselves.
In this setting the proposition is suddenly
advanced that some individuals, judicially labelled
as serious offenders, can be shown to be biologically
different from others not so labelled. The difference
lies in the assertion that "serious offenders" bear
in their body cells a genetic abnormality which is
said to be linked with aggressive anti-social behavior. Again, as in Lombrosian days, the contention offers the comfort and reassurance of a
clear cut, qualitative distinction between normal
and abnormal individuals (or at least the worst of
them). It is interesting that the cases which have
received most attention as typifying the XYY
syndrome, involve the most bizarre, disturbed
and unacceptable behavior. In the process of
denying one's own criminal propensities, it is
extremely useful to accept the contention that
serious offenders may have genetic abnormalities
which predispose them to their crimes. This not
only goes a long way towards fulfilling naive
hopes for a single, all inclusive determinant of
criminality, but it also provides a convenient
moral advantage for both the community at
RICHARD G. FOX
large and those personally responsible for the
offender's welfare, for all are relieved from blame
for the behavioural consequences of what is a
purely biological accident.
Whatever may be the explanation for the publicity XYY abnormality has drawn to itself, the
great interest in the theory has led to other significant consequences. The most important of these
relates to the development of an XYY mythology.
It would be wrong to think that by demonstrating
that XYY abnormality constitutes an inadequate
foundation for an insanity defense, and by showing
that there are strong psychological reasons for
interest in the topic, the subject no longer deserves
the attention of criminologists. The substantive
and procedural rules applicable to the trial process
do not exhaust the subject matter of the criminal
law. Decisions made before and after the trial are
of equal concern to the criminal lawyer and criminologist. And the grounds upon which these decisions are made are not always to be found in
statutes, regulations, or common law. Personal
beliefs, institutional policies and community
attitudes are some of the factors operating at
these other stages in the criminal justice system.
Over a period of time beliefs develop as to the
characteristics of certain offender types and these
beliefs have an important impact on the various
decisions affecting those offenders, especially
sentencing and discharge decisions. These beliefs,
when they diverge significantly from reality, are
more properly described as myths. There have
been, and still are, a good number of these myths
operating in our criminal justice system. A good
example is the mythology surrounding sex offenders
-that they are dangerously over-sexed, that they
graduate from less serious to more serious sex
offences, that there is a high risk of recividism,
and that the victims are invariably innocent and
unsuspecting strangers. Research findings do not
support these views but, too often, sentences are
imposed in accordance with the folk-belief rather
than current knowledge. 94 Because XYY offenders
constitute a brand new classification of offender
type, one might have thought that here was an
opportunity for medical and social scientists to
come together to examine the phenomenon free of
the mythology which tends to attach to classifications which have been in vogue for much
longer periods. It might also be thought that
94
NAL
See GIGEROFF,
LAW (1968).
Vol. 62
sound decisions could be made in relation to the
disposition of XYY individuals on the basis of
those research findings. Unhappily, it is obvious
that in the five years following the first major
research publications a mythology has built up
around the XYY male which extends to the
definition of the syndrome, the nature of the
offences committed, and the offender's rehabilitative potential. Very little of this is warranted by
the information in hand. Yet this mythology is
not only beginning to shape the limits of further
research, it is also seriously presented as the basis
of recommendations for far reaching legislative
and administrative action within the criminal
justice system. For instance, Professor McWhirter
of the Department of Genetics in the University
of Alberta, in a recent letter to Science, advocated
the following:
All boys and men who are under lawful restraint
should be classified into XY and XYY categories
so that the best treatment can be ascertained and
carried out.... Where actions in tort lie against
the state or its agents or both, each chromosomal
type of delinquent, if not segregated, might suethe XY for the gross negligence, and perhaps
assault, of the state which is confining him in an
environment known to be prejudicial to his chances
of reform-and the XYY, because he is being
negligently and cruelly deprived of the treatment
and research which his condition requires. Subsequent victims of an XYY whom the state had
negligently failed to diagnose despite confinement
after a criminal act should also have an action in
some jurisdictions. The probability factor makes
the criminal XYY a predictably dangerous person
and the standards of the duty to take care should
accordingly be raised.'1
In the near future the question whether legislative policies are to be framed, and administrative
decisions made, in accordance with XYY mythology or XYY reality may have to be faced. McWhirter's letter calls for action on the basis of the
mythology, namely that XYY males are psychopaths of uncontrollably aggressive temperament.
The reality is that XYY males in an institutional
setting are less violent or aggressive when compared to matched chromosomally normal fellow
inmates; and their criminal histories involve
crimes against property rather than persons. XYY
individuals who do not exhibit forms of psychiatric deviance or criminal behavior have already
been reported and social, familial and other non-
SEXUAL DEVIATIONS IN THE CRIMI-
96164 SCIENCE 1117 (1969).
1971]
THE XYY OFFENDERS
genetic environmental factors have not yet been
ruled out as the primary determinants of the
characteristics attributed to the extra Y chromosome. Even the generally accepted link with a
tendency towards height requires further investigation. There are so many unknown factors that
all of the research findings available to date must
be considered with considerable circumspection.
If the mythology wins out, one can expect that
the major role played by the discovery of an
XYY constitution in an offender will be in relation to his sentencing, institutionalization and, at
a later stage, his parole eligibility and discharge.
The XYY offender will risk longer sentences of
imprisonment, not for purposes of deterrence,
vengeance or rehabilitation, but simply out of a
desire on the part of the judge to isolate him in
order to protect the community from danger.
Similarly, the parole board may deny parole to an
otherwise eligible prisoner on the ground that he
has an XVY constitution which, in their opinion,
substantially increases the risk of him recidivating.
The cost to the individual XYY offender in terms
of his personal suffering through longer sentences
and decreased parole eligibility will be considerable.
We are cruel enough to our prisoners under the
guise of rehabilitating them without having to add
additional false justification for that cruelty. Research must proceed in the exposition of this
phenomenon but, in the present state of knowledge,
no one should be subjected to any additional sanction or suffer any other disability on account of
the finding in that person of an XYY chromosome
abnormality.